Nearly a century ago, journalist Napoleon Hill studied over 500 self-made millionaires, including Andrew Carnegie, Henry Ford, and Charles M. Schwab. His interviews and research culminated in the 1937 bestseller, "Think and Grow Rich."

While Hill is most known for his personal finance classic, which is a favorite of "Shark Tank" judges Robert Herjavec and Daymond John, he also wrote "The Path to Personal Power" in 1941, which was meant to be a handbook for those struggling to get back on their feet after the Great Depression. However, upon America's entry into WWII, the manuscript was forgotten about and only recently published, for the first time, in 2017.